Texas and Utah are the only states with 80-mph limits on some roadways. But Texas turned heads when lawmakers gave the green light to go to 85 if needed.

"The higher the speed limit, the more accidents there are, the more injuries and the more deaths," Jerry Johns, president of the Southwest Insurance Information Institute, told Reuters last year.

Eighty-five mph would be the second-highest posted speed limit in the world, according to the European auto rental firm Rhino Car Hire, Reuters reported. Some roads in Poland reportedly allow speeds of about 86 mph.

Texas hopes the faster toll road will help relieve one of the country's most congested interstates, between Austin and San Antonio.

"It's in a straight, flat area," TxDOT spokesman Mark Cross told Yahoo. "Safety is a priority. We want to make sure people understand that."